1. Field of the invention
The present invention relates to a vehicle, such as a rider-controlled working machine, having a four-wheel steering device.
2. Description of the Prior Art
Rider-controlled working machines such as agricultural machines and load carrying vehicles are required to have a small turning radius. To meet such a requirement, it has been proposed to steer front and rear wheels simultaneously in opposite directions as disclosed in Japanese Utility Model Publication No. 29-4015, U.S. Pat. Nos. 1,028,866 and 3,596,730, and Swiss Pat. No. 216,854.
The disclosed arrangements have a steering link mechanism partly disposed between the front wheels. Where an engine and a gear transmission are positioned between the front wheels, the steering link mechanism is disposed below the engine and the gear transmission and cannot be protected against interference with the road surface. In addition, difficulty is experienced with proper maintenance of the steering link mechanism thus located. If the steering link mechanism were positioned to be widely spaced from the road surface, then the height of the vehicle from the ground would be undesirably increased a corresponding amount.
The present invention has been made in an effort to eliminate the drawbacks of the conventional vehicles with four-wheel steering mechanisms.